Log grapple

ABSTRACT

A log grapple having use in grapple-yarding and log-loading operations is characterized by a pair of crossed jaws pivotally joined about one-third of the length thereof from their upper ends, a supporting and closing line attached to one of the jaws and extending about a sheave wheel attached to the other of the jaws for closing the jaws around a log on upward pull of the line, and an opening line attached to either of the jaws for opening the jaws when pulled upwardly.

United States Patent 1,343,057 6/1920 Lee 294/118 1,460,397 7/ 1923 Zehrer.. 294/118 1,471,448 10/1923 Burroughs 294/1 18 2,232,564 2/ 1941 Schwarz 294/1 18 X 2,452,452 10/ 1948 Girnas 294/112 2,786,709 3/1957 Wirkkala 294/1 18 3,317,235 5/ 1967 Botten 294/118 X Primary ExaminerEvon C. Blunk Assistant ExaminerW. Scott Carson XiiSTiXEE'TIF la pigiaiagigmgiam y;rdm and log-loading operations is characterized by a pair of crossed jaws pivotally joined about one-third of the length thereof from their upper ends, a supporting and closing line attached to one of the jaws and extending about a sheave wheel attached to the other of the jaws for closing the jaws around a log on upward pull of the line, and an opening line attached to either of the jaws for opening the jaws when pulled upwardly.

PATENTEDUET 12 m 3,612,597

ALBERT R. WIRKKALA INVENTOR.

ATTORNEYS L06 GRAPPLE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to improvements in grapples used primarily in logging operations.

2. Prior Art Relating to the Disclosure Log grapples used at the present time for handling logs and for grapple yarding include a relatively heavy frame to which the jaws of the grapple are attached. Illustrative of such grapples are those disclosed and illustrated in US. Pat. Nos: 2,761,727; 2,786,709; 3,043,620; 3,082,031; 3,102,752; and 3,245,712. The log grapple of this invention is an improvement over log grapples of the type disclosed in the above-mentioned patents. Grapples of the type disclosed in the above patents are used extensively in logging operations in the western United States and Canada and other locations to load logs onto logging trucks and trailers, to retrieve logs from log ponds, and to load the logs onto railroad flatcars. Grapples of this type are also being used in grapple yarding. When used in grapple yarding it is preferred that the log grapple be as light as possible yet be safe to use, have an adequate grip to hold the log, and easily opened and closed by power means.

SUMMARY OF THE INVENTION This invention is directed to improvements in log grapples and comprises broadly a pair of crossed jaws pivotally joined about one-third of the length thereof from their upper ends and designed to have the log engaging jaws overlap each other on closing, a sheave wheel attached to the first of the jaws above their pivotal connection point, an opening line attached to either of the jaws below the point of their pivotal connection for opening the jaws, and a supporting and closing line attached to the second of the jaws above the point of their pivotal connection and extending about the sheave wheel. Tensioning the supporting and closing line causes the jaws to close and apply squeezing pressure against a log held therebetween. Tensioning of the opening line and slacking of the supportingand closing line causes the jaws to open to release a log held therebetween.

It is a principal object of this invention to provide a log grapple of less weight and height; substantially less expensive; easier to manufacture; yet one which is ruggedly constructed. The grapple is both power opened and power closed.

It is further object to provide a log grapple that is capable of opening and closing relatively fast and one which is so constructed to insure stability and safety.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of the present grapple in partly closed position;

FIG. 2 is a side view of the grapple of FIG. 1 with the lower portion of the jaws not shown;

FIG. 3 is a plan view of a modified version of the grapple of this invention; and

FIG. 4 is an expanded partial side view of FIG. 3 of the sheave around which the lifting and closing line is extended.

DETAILED DESCRIPTION OF THE INVENTION The grapple of this invention comprises a pair of crossed jaws l and 12, substantially alike in size and construction, pivotally joined at a point about one-third of the length thereof from their upper ends by a pivot pin 14. The jaws have oppositely facing arcuate log-engaging surfaces 16 and 18 f amed thereon at their lower ends. Points 20 and 22 on each of the log-engaging surfaces help hold a log engaged between the jaws firmly in place. The jaws l0 and 12 are made and joined so that the log-engaging portions will overlap on closing. This enables the jaws to be used in logging operations where small diameter logs are encountered.

'Io suspend, open and close the jaws two lines are used. The lines may be heavy cable, chains or other conventional material capable of withstanding the stresses normally incurred in logging operations. The supporting and closing line 28 has one end secured to jaw 12 at its upper end by holding means 25 or other suitable means. Line 28 extends from its point of attachment to jaw 12 around block 26 attached to jaw 10 near the upper end thereof. Line 28 functions to suspend and close the jaws of the grapple on winding in or tensioning of the line and is commonly referred to as the closing or load line. Block 26 is pivotally mounted to jaw 10 as shown in FIG. 1. A sheave 27 can be employed in place of block 26 as shown in FIG. 3. To strengthen the grip of the jaws and increase the holding force thereof an additional block or sheave can be secured to the upper end of jaw 12. Line 28 can then be extended around the sheave or block and attached to block 26 or sheave 27.

Power opening of the jaws is the function of opening line 34. Line 34 may be secured to either of the jaws at a point approximately midway between the point of the pivotal connection of the jaws and the lower end thereof as shown in FIG. 3. Preferably line 34 is secured at one end to the upper end of one of the jaws. From that point of attachment line 34 then passes downwardly and around a block or sheave 30 attached to either of the jaws at a point approximately midway between their point of pivotal connection and the lower end of the jaws, and then upwardly to a winding drum (not shown).

The log grapple of this invention can be used for loading logs in conjunction with the conventional heel boom loader or it can be used with other types of loaders. Substantially the same structure and mode of operation can be employed in a three or four point grapple. The grapple is also useful in grapple-yarding operations because it is light in weight relative to other commonly used log grapples.

In operation the grapple is first opened by line 34 and then lowered about a log by paying out line 28. Tension in line 34 is then released and line 28 is tensioned to lifl and close the grapple about the log and apply squeezing pressure against the log to hold it securely therebetween. As the log-engaging por tions of the jaws have no lateral extensions along their lengths they are free to overlap in closing, thus enabling the grapple to be used in lifting and loading small diameter logs. Pads may be inserted along the inner edges of the jaws to give a balanced and directly opposed gripping action when the jaws are closed against a log.

A primary advantage of the grapple of this invention is its simplicity of construction which makes it less expensive to build and less expensive to maintain. As the grapples does not need nor have an upper crossbar or frame to which the jaws are attached its height is substantially less than presently used log grapples. This is a distinct advantage, particularly when the grapple is used in conjunction with a conventional heel boom loader, in that the fairleader of the loader does not need to be raised as high as previously.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a log grapple comprising a pair of arcuately shaped and crossed jaws pivotally joined at a point about one-third of the length thereof from their upper ends and including log-engaging portions,

a first sheave wheel rotatably mounted in a block, said block being pivoted attached to the first of the jaws above the point of their pivotal connection and adjacent the upper end thereof,

an opening line attached to one of the jaws below the point of their pivotal connection,

a supporting and closing line attached to the second of the jaws above the point of their pivotal connection and extending about the first sheave wheel, the winding in of the supporting and closing line causing said line to assume a direct line position in a vertical and horizontal plane and causing the jaws to close and apply squeezing pressure against a log held therebetween, and winding in of the opening line causing the jaws to open on release of the tension in the supporting and closing line. 

1. In a log grapple comprising a pair of arcuately shaped and crossed jaws pivotally joined at a point about one-third of the length thereof from their upper ends and including log-engaging portions, a first sheave wheel rotatably mounted in a block, said block being pivoted attached to the first of the jaws above the point of their pivotal connection and adjacent the upper end thereof, an opening line attached to one of the jaws below the point of their pivotal connection, a supporting and closing line attached to the second of the jaws above the point of their pivotal connection and extending about the first sheave wheel, the winding in of the supporting and closing line causing said line to assume a direct line position in a vertical and horizontal plane and causing the jaws to close and apply squeezing pressure against a log held therebetween, and winding in of the opening line causing the jaws to open on release of the tension in the supporting and closing line. 